I've tried to refine the above specs a little, and came up with this:
There always has to be one person who pushes the purse strings (no insinuation meant) and it is normally myself, sorry!
You mentioned wanting an mATX rig too, Well how about ITX?
YOUR BASKET
1 x
Asus Radeon R9 280X DirectCUII OC 3072MB GDDR5 PCI-Express Graphics Card £239.99
1 x
Intel Core i5-4690K 3.50GHz (Devil's Canyon) Socket LGA1150 Processor - Retail £189.95
1 x
Asus VE247H 24" Widescreen LED Multimedia Monitor - Black £129.95
1 x
Gigabyte Z97N-WIFI Intel Z97 (Socket 1150) DDR3 Mini ITX Motherboard £103.99
1 x
Corsair Obsidian Series 250D Mini ITX Compact Gaming Case - Black (CC-9011047-WW) £71.99
1 x
Kingston HyperX 8GB (2x4GB) PC3-17100C11 2133MHz Dual Channel Kit - Black/Red (HX21C11BRK2/8-OC) £61.99
1 x
Antec Kúhler H2O 1220 Series 4 High Performance Liquid CPU Cooler £60
1 x
Intel 320 Series 120GB Internal SSD SATA 3GB/s 2.5" 7mm (SSDSA2BW120G3) £59.99
1 x
NZXT Hale Power 90+ 550W '80 Plus Gold' Power Supply £43.99
1 x
Seagate Barracuda 7200RPM 1TB SATA 6Gb/s 64MB Cache - OEM (ST1000DM003) HDD £43.99
Total : £1,028.75 (includes shipping : £19.10).
Like i mentioned, a little over budget. But why is it worth it?
GPU:
The 280X is a wonderful card, it will blast through 1080p with ease and will manage with higher resolutions too. The DCUII is one of the best coolers for this card; silent, cool and stunning to behold. (Just so you know, i have checked and it will fit in the case, though there isn't a lot of room spare, especially up top)
Case:
Mini ITX, Top window, solid construction. Perfect.
Cooler:
Maybe a bit over the top, but its at a stunning price point and is well worth the money. It adds to the builds aesthetics while allowing high OC abilities.
Motherboard:
It has wifi included, which is cool.
Basically, this wasn't to budget for a few reasons, mainly aesthetic. I know that may not bother you now but you'll be seeing this everyday. I (used to) look at my rig day to day just to see its magnificence (before i downgraded due to 'reasons'). For an extra £30 having something pleasing to look at and equipped with good overclocking hardware is something worth thinking about.